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X-ray diffraction investigation of amorphous calcium phosphate and hydroxyapatite under ultra-high hydrostatic pressure

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International Journal of Minerals,Metallurgy and Materials 2015年第11期22卷 1225-1231页

作者： Elisa Lam Qinfen Gu Peter J.Swedlund Sylvie Marchesseau Yacine Hemar School of Chemical Sciences The University of Auckland Australian Synchrotron Université Montpellier 2 UMR IATE Pl.E Bataillon34095 Montpellier cedex 5 France

The changes in the crystal structures of synthetically prepared amorphous calcium phosphate（ACP） and hydroxyapatite（HAP） in water（1：1 mass ratio） were studied by synchrotron X-ray diffraction（XRD） under ultra-high hydrostatic pressures as high as 2.34 GPa for ACP and 4 GPa for HAP. At ambient pressure, the XRD patterns of the ACP and HAP samples in capillary tubes and their environmental scanning electron micrographs indicated amorphous and crystalline characteristics for ACP and HAP, respectively. At pressures greater than 0.25 GPa, an additional broad peak was observed in the XRD pattern of the ACP phase, indicating a partial phase transition from an amorphous phase to a new high-pressure amorphous phase. The peak areas and positions of the ACP phase, as obtained through fitting of the experimental data, indicated that the ACP exhibited increased pseudo-crystalline behavior at pressures greater than 0.96 GPa. Conversely, no structural changes were observed for the HAP phase up to the highest applied pressure of 4 GPa. For HAP, a unit-cell reduction during compression was evidenced by a reduction in both refined lattice parameters a and c. Both ACP and HAP reverted to their original structures when the pressure was fully released to ambient pressure.

关键词： calcium phosphate hydroxyapatite high hydrostatic pressure X-ray diffraction

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Mechanics of granular column collapse in fluid at varying slope angles

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Journal of Hydrodynamics 2017年第4期29卷 529-541页

作者： K.Kumar J.-Y.Delenne K.Soga Computational Geomechanics Research Group Department of Engineering University of Cambridge iate UMR 1208 INRA-CIRAD-Montpellier Supagro-UM2 University of Montpellier 2 Department of Civil and Environmental Engineering University of California

This paper investigates the effect of initial volume fraction on the runout characteristics of collapse of granular columns on slopes in fluid. 2-D sub-grain scale numerical simulations are performed to understand the flow dynamics of granular collapse in fluid. The discrete element method（DEM） technique is coupled with the lattice Boltzmann method（LBM）, for fluid-grain interactions, to understand the evolution of submerged granular flows. The fluid phase is simulated using multiple-relaxation-time LBM（LBM-MRT） for numerical stability. In order to simulate interconnected pore space in 2-D, a reduction in the radius of the grains（hydrodynamic radius） is assumed during LBM computations. The collapse of granular column in fluid is compared with the dry cases to understand the effect of fluid on the runout behaviour. A parametric analysis is performed to assess the influence of the granular characteristics（initial packing） on the evolution of flow and run-out distances for slope angles of 0 °, 2.5°, 5 ° and 7.5 °. The granular flow dynamics is investigated by analysing the effect of hydroplaning, water entrainment and viscous drag on the granular mass. The mechanism of energy dissipation, shape of the flow front, water entrainment and evolution of packing density is used to explain the difference in the flow characteristics of loose and dense granular column collapse in fluid.

关键词： Lattice Boltzmann method(LBM) discrete element method(DEM) granular column collapse granular flows hydroplaning water entrainment viscous drag

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One-pot activation and pyrolysis of Moroccan Gelidium sesquipedale red macroalgae residue:production of an efficient adsorbent biochar

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Biochar 2019年第4期1卷 401-412页

作者： Saida Tayibi Florian Monlau Nour-elhouda Fayoud Abdallah.Oukarroum Youssef Zeroual Hassan Hannache Abdellatif Barakat iate Montpellier SupAgroINRAEUniversite de MontpellierMontpellierFrance Mohammed VI Polytechnic University(UM6P) BenguerirMorocco APESA Pôle ValorisationCap EcologiaLescarFrance LIMAT Facultédes Sciences Ben M’SikUniversitéHassan II de CasablancaCasablancaMorocco Situation Innovation OCP GroupComplexe industriel Jorf LasfarEl

One-pot chemical activation and pyrolysis process was developed for biochar production from red macroalgae residue of Gelidium *** macroalgae residue was activated by various catalysts(KOH,NaOH,H_(3)PO_(4),and CH_(4)ON_(2))with the two concentrations(2.5 wt%and 5 wt%)using a pulverization system followed by slow pyrolysis at 500℃.The activated biochars showed a porous morphology with an increase of water holding capacity compared to the unactivated *** properties of activated biochar observed by further characterization(i.e.,FTIR,SEM,TGA)revealed their feasibility to be used as an *** results of adsorption experiment confirmed that adsorption was dependent not only on the surface area but also on the surface charge,and functional *** sorption performance of activated biochars(AcBC),in terms of the adsorption of methylene blue,was comparable to commercial activated charcoal(Norit^(■)).NaOH(2.5 wt%)-activated biochar had the removal efficiency of 87%versus 97%for commercial activated charcoal.

关键词： Red macroalgae residue Chemical activation Slow pyrolysis Adsorption

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Lipid Profile and Antioxidant Activity of Macadamia Nuts (<i>Macadamia integrifolia</i>) Cultivated in Venezuela

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Natural Science 2015年第12期7卷 535-547页

作者： Alejandra Rengel Elevina Pérez George Piombo Julien Ricci Adrien Servent María Soledad Tapia Olivier Gibert Didier Montet Instituto de Ciencia y Tecnología de Alimentos Facultad de Ciencias Universidad Central de Venezuela Caracas Venezuela Cirad UMR Iate Campus de la Gaillarde 2 place Pierre Viala Montpellier France Cirad UMR 95 Qualisud TA B-95/16 73 rue Jean-Francois Breton Montpellier France

Macadamia nuts (Macadamia integrifolia) grown in Venezuela have showed an average total fat content of 70%. Oleic acid (18:1) was the main monounsaturated fatty acid (MUFA) (51.3%), followed by palmitoleic acid (16:1, 22.6%). The content of polyunsaturated fatty acids (PUFAs), C18:2 and C18:3 represented 5.4%. Thus, MUFAs and PUFAs together constituted more than 80% of the total fatty acids present. Trans-vaccenic acid was also present (3%). As regards to other phytochemical compounds, tocopherols and tocotrienols were not found in the sample, but the presence of squalene was *** antioxidant activity (44.2%) of the extract was produced by the phytochemicals present.

关键词： Lipids Antioxidant Activity Fatty Acids Macadamia Nut Phytochemical Compounds

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